Protection device for intake pipes of lubricating coolant pumps

ABSTRACT

A protective pot, adapted to be mounted to a mouth of an intake pipe of a lubricating coolant pump for a machine tool, includes a closed bottom, a closed peripheral wall and at least one suction window arranged at a distance above the bottom.

The present application relates, according to claim 1, to a protective pot which is adapted to be fastened to the mouth of an intake pipe of a lubricating coolant pump for machine tools.

Such a protective pot is known from DE 1 240 718 C (see suction basket 3 in FIG. 1), but is not described in detail.

From DE 90 00 713 U1, further, a protection device against intake of dirt particles has become known, which is adapted to be mounted to the mouth of an intake pipe of a lubricating coolant pump for machine tools, wherein a liquid collector pot is shaped to provide a distance between the intake openings and the bottom of the reservoir, so that deposits on the bottom are prevented from being sucked in.

The construction according to the present claim 1 differs from this in that the pot-shaped protection device has a closed peripheral wall and at least one suction window in a distance above the bottom.

A protective pot for the mouth of an intake pipe with a partly closed peripheral wall has become known from DE 28 47 607 A1. However, there, the intake openings are arranged directly at the bottom, which involves the risk that deposits are sucked in. A prior art that would be closer to the invention has not been found, and since the cited prior art does not suggest the construction as indicated in claim 1, the grant of a patent can be promised.

The further claims 2 to 8 are also allowable, an amendment being necessary only in claim 8, as shown in the Annex.

In the introductory part of the description, the prior art according to the citations will have to be discussed. A reference to DE 198 05 411 C2 is not necessary, because this document does not disclose a protection device according to claimed species.

Clean copies of the amended sheets will have to be filed. With the present documents, the grant of a patent is not yet possible.

BACKGROUND OF THE INVENTION

The invention relates to lubricating coolant pumps for machine tools, comprising an intake pipe that is immersed in a lubricating coolant reservoir.

In machine tools, the tools and the workpieces are cooled and lubricated during the machining processes by means of a lubricating coolant emulsion or an oil. The emulsion dripping off from the tool and the workpiece is collected, filtered and stored in a lubricating coolant reservoir that is typically arranged in the machine bed and from which the emulsion is sucked by means of the lubricating coolant pump and is conveyed again to the working area of the machine, so that a closed lubricating coolant circuit is formed.

Since the lubricating coolant emulsion frequently contains abrasive contaminants such as metal chips and the like, lubricating coolant pumps are in many cases configured as centrifugal pumps.

DE 198 05 411 C2 discloses a lubricating coolant pump for machine tools, comprising a conveyor screw that is arranged in the intake pipe. Because of the very low mechanical strain on the pumped liquid, this pump is particularly suited for modern lubricating coolant emulsions which have a strong foaming tendency.

In view of an increased technical use of silicon carbide, one is increasingly confronted with the problem to pump lubricating coolant emulsions that are contaminated with particles of silicon carbide. However, because of its high hardness, silicon carbide leads to an increased wear of the lubricating coolant pumps.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a device that permits to establish, e.g., by means of a screw pump, a lubricating coolant circuit that is less sensitive to silicon carbide particles contained in the lubricating coolant emulsion.

According to the invention, this object is achieved by a protective pot that is adapted to be mounted to the mouth of an intake pipe of a lubricating coolant pump for machine tools. The protective pot has a closed bottom, a closed peripheral wall and at least one suction window arranged in a distance above the bottom. The suction window is for example formed in the peripheral wall.

The invention further provides an intake pipe for a lubricating coolant pump for machine tools, having such a protective pot mounted to one end of the intake pipe.

In particular, the invention provides an intake pipe for a lubricating coolant pump for machine tools, having such a protective pot, which is arranged at a lower end of the intake pipe, wherein an opening of the intake pipe is arranged inside of the protective pot. Preferably, the opening of the intake pipe is arranged below the at least one window.

Another subject of the invention is a lubricating coolant pump for machine tools, having such an intake pipe with protective pot. For example, the intake pipe is immersed with its protective pot in a lubricating coolant reservoir.

The protective pot according to the invention prevents that the opening of the intake pipe arranged in the protective pot is positioned directly above the bottom of the lubricating coolant reservoir. The bottom of the protective pot is arranged between the opening of the intake pipe and the bottom of the lubricating coolant reservoir. The upwardly projecting closed wall of the protective pot assures that chips, silicon carbide particles or other contaminants that accumulate on the bottom of the lubricating coolant reservoir will not or to a strongly reduced extent enter into the interior of the protective pot and hence into the intake pipe. This helps to significantly reduce the wear of the lubricating coolant pump.

In a conventional device having an intake pipe or an intake neck of a lubricating coolant pump, it is necessary for minimizing the intake of chips and other contaminants, to arrange the opening of the intake pipe or intake neck in a certain distance, e.g. several centimeters, above the bottom of the lubricating coolant reservoir. The deeper the intake pipe or the intake neck is immersed into the lubricating coolant reservoir, the more likely will chips or other contaminants be sucked in. On the other hand, the larger the distance between the intake opening and the bottom of the lubricating coolant reservoir, the larger is the amount of lubricating coolant emulsion that is necessary for assuring a sufficient fill level of the lubricating coolant reservoir. Thus, it is a complex task to mount the lubricating coolant pump. Moreover, a too little height of the intake pipe above the bottom of the lubricating coolant reservoir will be revealed only by an increased wear of the pump. Then, however, the damage has occurred already.

These drawbacks are efficiently avoided by the solution according to the invention.

Useful embodiments of the invention are indicated in the dependent claims.

Preferably, the wall of the protective pot is essentially cylindrical. It may however also be rounded, for example, in the lower part or may form a half sphere together with the bottom.

In a preferred embodiment, a lid is arranged above the at least one suction window. When the level of lubricating coolant emulsion in the lubricating coolant reservoir is close above the protective pot, the lid serves to prevent an air funnel from being formed due to the suction action of the pump.

Preferably, the at least one suction window is arranged in the wall, e.g. in the top part of the wall, and extends up to the lid.

Preferably, the protective pot has at least one sleeve for attaching the protective pot to the intake pipe. For example, the sleeve has a threading for a fastening screw with which it is fastened to the intake pipe. The protective pot may be fastened by means of the sleeve in the desired height and position, respectively, of the intake pipe and, moreover, is detachable.

The sleeve is arranged at the lid, for example, in order to connect the protective pot to an intake pipe that passes through the lid.

As an alternative, for being attached to the mouth of the intake pipe, the protective pot may have a connector neck that extends essentially at a right angle from the peripheral wall. For example, the connector neck is arranged at the peripheral wall at the level of the at least one suction window. The connector neck may for example have a threading for being screw-fastened to the intake pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments will be explained in detail in conjunction with the drawings, wherein:

FIG. 1 is a perspective view of a protective pot mounted on an intake pipe for a lubricating coolant pump;

FIG. 2 is a schematic view of a lubricating coolant pump having an intake pipe and a protective pot fastened thereto and immersed in a lubricating coolant reservoir; and

FIG. 3 is a sectional view of a protective pot having a horizontal connector neck.

DETAILED DESCRIPTION

The protective pot 10 shown in FIG. 1 has a closed cylindrical peripheral wall 12 formed in one piece with a closed plane bottom 14. The wall 12 is connected at its top edge to a plane lid 16. The bottom 14 and the lid 16 are disk shaped, the lid 16 having a diameter slightly larger than that of the bottom 14 and the cylindrical wall 12.

An intake pipe 18 of a lubricating coolant pump 20 (FIG. 2) is passed centrally through the lid 16. The intake pipe 18 is beveled at its lower end at an angle of approximately 45 i, whereby an intake opening 22 is formed. The latter is arranged in the lower portion of the protective pot 10. At its lowest point, the intake pipe 18 almost reaches the bottom 14.

The wall 12 has in its upper portion four rectangular suction windows 24 distributed over the periphery of the pot. The lower edges 26 of the suction windows 24 are located in a height that is still significantly above the highest point of the intake opening 22. The suction windows 24 extend upwardly up to the lid 16 which covers the suction windows 24.

Together with the part of the wall 12 located below the suction windows 24, the bottom 14 forms a closed lower part of the protective pot 10. This closed part assures that liquid can enter into the protective pot 10 only through the suction windows 24 which are arranged in a height of several centimeters, for example, above the bottom 14.

The protective pot 10 is fastened to the intake pipe 18 by means of a lower sleeve 28 that is tightened on the intake pipe 18 with a fastening screw 30. The sleeve 28 is arranged under the lid 16 approximately in the height of the suction windows 24 and is, for example, connected to the lid 16. Above the lid 16, an upper sleeve 32 is also tightened on the intake pipe 18 with a fastening screw 30.

The upper sleeve 32 may for example be mounted on the intake pipe 18 separately of the lid 16, so as to define the mounting position of the protective pot 10 when the same is detached. Optionally, however, the upper sleeve 32 is rigidly connected to the lid 16. It is also conceivable that the lower part of the protective pot 10 having the bottom 14 and the wall 12 is rigidly connected to the lower sleeve 28, whereas the lid 16 forms a separate member.

FIG. 2 shows schematically a lubricating coolant pump 20 having the intake pipe 18 and an outlet pipe 34. For example, the lubricating coolant pump 20 is a screw pump. The protective pot 10 is mounted on the lower end of the intake pipe 18 as in FIG. 1. The intake pipe 18 together with the protective pot 10 is immersed in a lubricating coolant reservoir 36 of a machine tool.

In FIG. 2, the lubricating coolant reservoir 36 is filled with a lubricating coolant emulsion 40 up to a level clearly above the protective pot 10. This emulsion flows into the protective pot 10 through the suction windows 24 and is pumped through the intake opening 22 by the pump 20.

In the lower part of the lubricating coolant reservoir 38, accumulations of metal chips and silicon carbide particles 42, for example, have been indicated as dashed lines. These chips and particles sink down in the lubricating coolant emulsion 40 due to their weight. Although the intake opening 22 is arranged close to the bottom of the lubricating coolant reservoir 36, the chips and silicon carbide particles 42 are not sucked in by the pump 20, however, because the lubricating coolant emulsion is sucked in only through the suction windows 24 that are arranged at a higher level. In this way, the protective pot 10 efficiently prevents an excessive wear of the lubricating coolant pump 20.

When the level of the lubricating coolant emulsion 40 in the lubricating coolant reservoir 36 decreases to approximately the top edge of the protective pot 10, the lid 16 serves to prevent the suction action of the pump 20 from creating an air funnel. Optionally, however, the lid 16 may be dispensed with, so that the protective pot will essentially have the form of a pot with an open top, for example, connected to the sleeve 28 by cross bars, for example.

FIG. 3 shows another embodiment of a protective pot 10′, and like or similar parts have been designated with like reference numerals as in FIGS. 1 and 2.

The protective pot 10′ of FIG. 3 differs from the protective pot 10 of FIGS. 1 and 2 essentially in that an intake pipe of a lubricating coolant pump does not penetrate the lid 16 of the protective pot 10′, but the protective pot 10′ has a horizontally directed connector neck 50 which may for example be screwed with a threading 52 to an intake pipe of the lubricating coolant pump, said intake pipe extending horizontally, at least in an end portion thereof. Thus, the connector neck 50 prolongs the intake pipe and forms a lateral intake opening 22′ inside of the protective pot 10′. The connector neck 50 is arranged in the upper portion of the protective pot 10, approximately in the height of the intake windows 24.

In this embodiment, the lid 16 has the same diameter as the bottom 14. The protective pot 10′ is formed for example with three angularly distributed, approximately rectangular suction windows 24. These extend again upwardly, approximately up to the lid 16.

As the protective pot 10 of FIGS. 1 and 2, the protective pot 10′, thanks to its closed lower part, assures that liquid can only enter into the protective pot 10′ through the suction windows 24 which are arranged in a height of several centimeters, for example, above the bottom 14. In this way, it is again prevented that possible chips or silicon carbide particles which have accumulated in the lower part of a lubricating coolant reservoir, are sucked in by the pump. Thus, the protective pot 10 according to FIG. 3 prevents an excessive wear of the lubricating coolant pump due to metal chips or silicon carbide particles being sucked in, also for lubricating cooling pumps the intake pipe of which extends horizontally, at least in the vicinity of the lower end thereof. 

1. A protective pot, adapted to be mounted to a mouth of an intake pipe of a lubricating coolant pump for a machine tool, comprising a closed bottom, a closed peripheral wall and at least one suction window arranged in a distance above the bottom.
 2. The protective pot according to claim 1, wherein the peripheral wall is essentially cylindrical.
 3. The protective pot according to claim 1, wherein a lid is arranged above the at least one suction window.
 4. The protective pot according to claim 3, wherein the at least one suction window is arranged in the peripheral wall and extends up to the lid.
 5. The protective pot according to claim 1, comprising at least one sleeve for mounting the protective pot to the intake pipe.
 6. The protective pot according to claim 1, comprising a connector neck to be mounted to the mouth of the intake pipe, said connector neck projecting from the peripheral wall essentially at a right angle.
 7. An intake pipe for a lubricating coolant pump for machine tools, wherein a protective pot according to any of the preceding claims is arranged at one end of the intake pipe.
 8. The intake pipe according to claim 7, wherein the protective pot is arranged at a lower end of the intake pipe, and an intake opening (22) of the intake pipe is arranged inside of the protective pot.
 9. The intake pipe according to claim 8, wherein the intake opening is arranged below said at least one window.
 10. A lubricating coolant pump for machine tools, comprising an intake pipe according to any of the claims 7 to
 9. 